A former NSW Police officer who allegedly assaulted a teenager while on duty on the Northern Rivers will undergo a mental health assessment.

In September 2019, officers attached to Richmond Police District commenced an extensive review regarding an alleged assault in Casino involving a then 39-year-old senior constable and a 17-year-old teenage boy.

The officer, formerly attached to Richmond Police District, was on duty at the time of the alleged incident.

The now 40-year-old man was charged with common assault on February 7 for the alleged incident.

When his matter was mentioned in Lismore Local Court on March 22, the man's solicitor applied for an adjournment to allow his client to undergo a mental health assessment.

Magistrate Jeff Linden adjourned the matter under Section 32.

He is no longer a member of the NSW Police Force.